CARBON nanotubes1 are expected to have a wide variety of interesting properties. Capillarity in open tubes has already been demonstrated2–5, while predictions regarding their electronic structure6–8 and mechanical strength9 remain to be tested. To examine the properties of these structures, one needs tubes with well defined morphologies, length, thickness and a number of concentric shells; but the normal carbon-arc synthesis10,11 yields a range of tube types. In particular, most calculations have been concerned with single-shell tubes, whereas the carbon-arc synthesis produces almost entirely multi-shell tubes. Here we report the synthesis of abundant single-shell tubes with diameters of about one nanometre. Whereas the multi-shell nanotubes are formed on the carbon cathode, these single-shell tubes grow in the gas phase. Electron diffraction from a single tube allows us to confirm the helical arrangement of carbon hexagons deduced previously for multi-shell tubes1.

Single-shell carbon nanotubes of 1-nm diameter

The interest in nanoscale materials stems from the fact that new properties are acquired at this length scale and, equally important, that these properties * To whom correspondence should be addressed. Phone, 404-8940292; fax, 404-894-0294; e-mail, mostafa.el-sayed@ chemistry.gatech.edu. † Case Western Reserve UniversitysMillis 2258. ‡ Phone, 216-368-5918; fax, 216-368-3006; e-mail, burda@case.edu. § Georgia Institute of Technology. 1025 Chem. Rev. 2005, 105, 1025−1102

Chemistry and properties of nanocrystals of different shapes.

Worldwide commercial interest in carbon nanotubes (CNTs) is reflected in a production capacity that presently exceeds several thousand tons per year. Currently, bulk CNT powders are incorporated in diverse commercial products ranging from rechargeable batteries, automotive parts, and sporting goods to boat hulls and water filters. Advances in CNT synthesis, purification, and chemical modification are enabling integration of CNTs in thin-film electronics and large-area coatings. Although not yet providing compelling mechanical strength or electrical or thermal conductivities for many applications, CNT yarns and sheets already have promising performance for applications including supercapacitors, actuators, and lightweight electromagnetic shields.

/pdf/carbon-nanotubes-present-and-future-commercial-applications-1nhq3xy4hh.pdf

Carbon Nanotubes: Present and Future Commercial Applications

Nanoparticles — particles in the size range 1–100 nm — are emerging as a class of therapeutics for cancer. Early clinical results suggest that nanoparticle therapeutics can
show enhanced efficacy, while simultaneously reducing side effects, owing to properties such as more targeted localization in tumours and active cellular uptake. Here, we
highlight the features of nanoparticle therapeutics that distinguish them from previous anticancer therapies, and describe how these features provide the potential for
therapeutic effects that are not achievable with other modalities. While large numbers of preclinical studies have been published, the emphasis here is placed on preclinical and clinical studies that are likely to affect clinical investigations and their implications for advancing the treatment of patients with cancer.

Nanoparticle therapeutics: an emerging treatment modality for cancer

Department of Materials Science, University of Patras, 26504 Rio Patras, Greece, Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vass. Constantinou Avenue, 116 35 Athens, Greece, Institut de Biologie Moleculaire et Cellulaire, UPR9021 CNRS, Immunologie et Chimie Therapeutiques, 67084 Strasbourg, France, and Dipartimento di Scienze Farmaceutiche, Universita di Trieste, Piazzale Europa 1, 34127 Trieste, Italy

Chemistry of Carbon Nanotubes

Molten salt mixtures have been tested in a redox mode as catalysts for the activation of methane at 750 °C. It is found that after pre-treatment with dioxygen a transition metal halide/ sodium vanadate melt can convert methane selectively to C2+ products in the absence of molecular oxygen. The melt can be reactivated by passing dioxygen. Electron paramagnetic resonance studies of the quenched samples showed that the transition metal ions are reduced by methane and can be reoxidised by dioxygen. It is also found that higher C2+ selectivity, C2+ yield and C2H4/C2H6 ratio are promoted by added transition metal chlorides and, surprisingly, also by the corresponding metal bromides. It supports the suggestion that surface modification by halogen is more important than gas radical reactions. Comparison of the molten mixtures under redox and cofeed conditions showed that the former gave a higher C2+ selectivity, but no oxygenated products whereas formaldehyde was only detected in the cofeed conditions.

Redox properties of molten salts for methane activation

An Introduction to the Chemistry of Molybdenum

Oxidative dimerization of sodium (aza-15-crown-5) dithiocarbamate affords bis(aza-15-crown-5)-thiuram disulphide, which exhibits dramatic changes in the dynamic 13C-{1H} n.m.r. spectrum upon addition of sodium ions.

Effects of sodium ions on the molecular dynamics of bis(aza-15-crown-5)thiuram disulphide

Studies on monovalent η-butadiene derivatives of niobium and tantalum

The reaction between rhenium atoms, benzene, and cyclohexene gives the compound Re(η-C6H6)(η-C6H8)H and the mixed valency dimer (η-C6H6)Re(µ-H)2Re(η-C6H8)2.

Synthesis of η-benzene-η-cyclohexa-1,3-diene derivatives of rhenium via reaction of rhenium atoms with benzene and cyclohexene: crystal structures of Re(η-C6H6)(η-C6H8)H and (η-C6H6)Re(µ-H)2Re(η-C6H8)2

Malcolm L. H. Green

Papers

Redox properties of molten salts for methane activation

An Introduction to the Chemistry of Molybdenum

Effects of sodium ions on the molecular dynamics of bis(aza-15-crown-5)thiuram disulphide

Studies on monovalent η-butadiene derivatives of niobium and tantalum

Synthesis of η-benzene-η-cyclohexa-1,3-diene derivatives of rhenium via reaction of rhenium atoms with benzene and cyclohexene: crystal structures of Re(η-C6H6)(η-C6H8)H and (η-C6H6)Re(µ-H)2Re(η-C6H8)2